Interpreting regression toward the mean in developmental research

"The fundamental nature of regression toward the mean is frequently misunderstood by developmental researchers. While errors of measurement are commonly assumed to be the sole source of regression effects, the latter also are obtained with errorless measures. The conditions under which regression phenomena can appear are first clearly defined. Next, an explanation of regression effects is presented which applies both when variables contain errors of measurement and when they are errorless. The analysis focuses on cause and effect relationships of psychologically meaningful variables. Finally, the implications for interpreting regression effects in developmental research are illustrated with several empirical examples."